Free radicals and inflammation: superoxide-dependent activation of a neutrophil chemotactic factor in plasma

Increased xanthine oxidase in the thalamus and putamen in depression

A growing body of literature suggests persistent and selective structural changes in the cortico-limbic-thalamic-striatal system in patients with recurrent depressive disorder (DD). Oxidative stress is thought to play a key role in these processes. So far, the main scientific focus has been on antioxidant enzymes in this context. For the first time, this proof of concept study examines the activity of the free radicals producing the enzyme, xanthine oxidase (XO), directly in the cortico-limbic-thalamic-striatal system of patients with recurrent depression. The activity of XO was ascertained in the cortico-limbic-thalamic-striatal regions in post-mortem brain tissue of patients with recurrent depressive episodes and individuals without any neurological or psychiatric history (7/7). We measured the XO activity in following brain areas: hippocampus, regio entorhinalis, thalamus, putamen and caudate nucleus. In this study, we report a significant increase of XO activity in the thalamus and the putamen of patients with depression. Our findings contribute to the growing body of evidence suggesting that oxidative stress plays a pivotal role in certain brain areas in recurrent depressive disorder.

The structural biochemistry of the superoxide dismutases

The discovery of superoxide dismutases (SODs), which convert superoxide radicals to molecular oxygen and hydrogen peroxide, has been termed the most important discovery of modern biology never to win a Nobel Prize. Here, we review the reasons this discovery has been underappreciated, as well as discuss the robust results supporting its premier biological importance and utility for current research. We highlight our understanding of SOD function gained through structural biology analyses, which reveal important hydrogen-bonding schemes and metal-binding motifs. These structural features create remarkable enzymes that promote catalysis at faster than diffusion-limited rates by using electrostatic guidance. These architectures additionally alter the redox potential of the active site metal center to a range suitable for the superoxide disproportionation reaction and protect against inhibition of catalysis by molecules such as phosphate. SOD structures may also control their enzymatic activity through product inhibition; manipulation of these product inhibition levels has the potential to generate therapeutic forms of SOD. Markedly, structural destabilization of the SOD architecture can lead to disease, as mutations in Cu,ZnSOD may result in familial amyotrophic lateral sclerosis, a relatively common, rapidly progressing and fatal neurodegenerative disorder. We describe our current understanding of how these Cu,ZnSOD mutations may lead to aggregation/fibril formation, as a detailed understanding of these mechanisms provides new avenues for the development of therapeutics against this so far untreatable neurodegenerative pathology.

Spin trapping and cytoprotective properties of fluorinated amphiphilic carrier conjugates of cyclic versus linear nitrones

Nitrones have been employed as spin trapping reagent as well as pharmacological agent against neurodegenerative diseases and ischemia-reperfusion induced injury. The structure-activity relationship was explored for the two types of nitrones, i.e., cyclic (DMPO) and linear (PBN), which are conjugated to a fluorinated amphiphilic carrier (FAC) for their cytoprotective properties against hydrogen peroxide (H(2)O(2)), 3-morpholinosynonimine hydrochloride (SIN-1), and 4-hydroxynonenal (HNE) induced cell death on bovine aortic endothelial cells. The compound FAMPO was synthesized and characterized, and its physical-chemical and spin trapping properties were explored. Cytotoxicity and cytoprotective properties of various nitrones either conjugated and nonconjugated to FAC (i.e., AMPO, FAMPO, PBN, and FAPBN) were assessed using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium (MTT) reduction assay. Results show that of all the nitrones tested, FAPBN is the most protective against H(2)O(2), but FAMPO and to a lesser extent its unconjugated form, AMPO, are more protective against SIN-1 induced cytotoxicity. However, none of the nitrones used protect the cells from HNE-induced cell death. The difference in the cytoprotective properties observed between the cyclic and linear nitrones may arise from the differences in their intrinsic antioxidant properties and localization in the cell.

The effect of physical exercise on endothelial function

Endothelium is essential for maintenance of health of the vessel wall and for the local regulation of vascular tone and structure and haemostasis. Regular physical exercise, which is known to promote a favourable cardiovascular state, may improve endothelial function via several mechanisms. Indeed, it augments blood flow and laminar shear stress, resulting in increased nitric oxide production and bioavailability. In this regard, the beneficial effects of training on endothelial function can be mediated in a number of ways, including synthesis of molecular mediators, changes in neurohormonal release and oxidant/antioxidant balance. On the other hand, physical exercise can also elicit systemic molecular pathways connected with angiogenesis and chronic anti-inflammatory action with consequent modification of the endothelial function. However, its benefit depends on the type and intensity of training performed. While strenuous exercise increases oxidative metabolism and produces a pro-oxidant environment, only regular moderate physical activity promotes an antioxidant state and preserves endothelial function. Thus, exercise may have a beneficial effect on the development of cardiovascular disease through preserving endothelial function.

Antioxidative and antimicrobial activity of Reynoutria japonica extracts

Ethanolic (50%, v/v) extract of Reynoutria japonica Houtt. rhizome from the Banja Luka region was prepared. The dry extract was dissolved in methanol, and total phenols content, antimicrobial and antioxidative activities were determined. The total phenols content was determined using modified Folin-Ciocalteu method, the antimicrobial activity by monitoring the optical density, and antioxidative activity by the method of quenching stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals by FRAP and ABTS metods. The antioxidative activity results were compared with control antioxidants: vitamin C, BHA and BHT. In order to determine the antimicrobial extract activity, E. coli, S. aureus and B. cereus were used as test microorganisms. The paper discusses the results of antimicrobial and antioxidative activeties of the R. japonica extract with respect to extract concentration as well as to total phenols content. The extract of R. japonica rhizome shows both, a significant overall antioxidant activity (29.84 mM (FeII)/g of extract) and high activity in quenching DPPH (IC50 = = 13.68 ?g/mL) and ABTS+ (99.1%) radicals. It was found that the R. Japonica extract had greater impact on growth rate reduction of B. cereus, E. coli, than S. aureus, expressed in percentages of growth rate, L, 73.6, 59.3 and 52.1% respectively. The greatest decrease in total bacterial count, M, was observed in S. aureus (71.9%), while the decrease in E. coli and B. cereus was approximately equal (about 50%). The total phenols content, expressed as mg of galic acid equivalents/g of extract was 664?15. The high antioxidant and significant antimicrobial activity of the R. japonica extract determined in this work is associated with extremely high total phenols content.

Cerulein pancreatitis: oxidative stress, inflammation, and apoptosis

Cerulein pancreatitis is similar to human edematous pancreatitis, manifesting with dysregulation of digestive enzyme production and cytoplasmic vacuolization, the death of acinar cells, edema formation, and infiltration of inflammatory cells into the pancreas. Reactive oxygen species are involved in nuclear factor-kappaB activation, cytokine expression, apoptosis and pathogenesis of pancreatitis. There is recent evidence that cerulein activates NADPH oxidase, which is a major source of reactive oxygen species during inflammation and apoptosis in pancreatic acinar cells. In addition, the Janus kinase/signal transducer and activator of transcription pathway has been suggested as being involved in inflammatory signaling in the pancreas. This review discusses the involvement of oxidative stress in inflammation and apoptosis in pancreatic acinar cells stimulated with cerulein as an in vitro model of pancreatitis.

Improved spin trapping properties by beta-cyclodextrin-cyclic nitrone conjugate

Spin trapping using a nitrone and electron paramagnetic resonance (EPR) spectroscopy is commonly employed in the identification of transient radicals in chemical and biological systems. There has also been a growing interest in the pharmacological activity of nitrones, and there is, therefore, a pressing need to develop nitrones with improved spin trapping properties and controlled delivery in cellular systems. The beta-cyclodextrin (beta-CD)-cyclic nitrone conjugate, 5-N-beta-cyclodextrin-carboxamide-5-methyl-1-pyrroline N-oxide (CDNMPO) was synthesized and characterized. 1-D and 2-D NMR show two stereoisomeric forms (i.e., 5S- and 5R-) for CDNMPO. Spin trapping using CDNMPO shows distinctive EPR spectra for superoxide radical anion (O2(*-)) compared to other biologically relevant free radicals. Kinetic analysis of O2(*-) adduct formation and decay using singular value decomposition and pseudoinverse deconvolution methods gave an average bimolecular rate constant of k = 58 +/- 1 M(-1) s(-1) and a maximum half-life of t(1/2) = 27.5 min at pH 7.0. Molecular modeling was used to rationalize the long-range coupling between the nitrone and the beta-CD, as well as the stability of the O2(*-) adducts. This study demonstrates how a computational approach can aid in the design of spin traps with a relatively high rate of reactivity to O2(*-), and how beta-CD can improve adduct stability via intramolecular interaction with the O2(*-) adduct.

Prophylactic evaluation of recombinant extracellular superoxide dismutase of Brugia malayi in jird model

The immunoscreening of Brugia malayi adult cDNA library with pooled endemic normal sera identified several seroreactive clones including, EC-SOD which contained a 612 bp insert and showed significant nucleotide and deduced amino acid sequence homologies with superoxide dismutase (SOD) of other nematode parasites. The SODs are known to play an important role in the protection of parasite against reactive oxygen species of the host. The coding region of the B. malayi EC-SOD (BmEC-SOD) was cloned and expressed in Escherichia coli followed by affinity purification on nickel agarose resin. Staining of native polyacrylamide gel for SOD activity of the expressed recombinant protein revealed that SOD activity inactivated by potassium cyanide and hydrogen peroxide but not by sodium azide, indicating presence of Cu/Zn-SOD. The rBm EC-SOD protein showed its activity over a broad range of pH.7.0-11.0. Further the immune protective activity of recombinant EC-SOD antigen was evaluated in susceptible host, jirds (gerbils) (Meriones unguiculatus) against B. malayi filarial infection. The immunized jirds showed 33.5% and 36% cytotoxicity against microfilariae and 42.8% and 45.5% cytotoxicity against infective larvae in in vitro antibody dependent cellular cytotoxicity (ADCC) assay and in in situ micropore chamber methods respectively. This study suggests that the rBm EC-SOD antigen could stimulate a partial protective immune response against microfilariae and infective larvae in experimental animals against filarial infection.

The protective role of cellular glutathione peroxidase against trauma-induced mitochondrial dysfunction in the mouse brain

Reactive oxygen species are believed to participate in the pathogenesis of traumatic brain injury (TBI). To evaluate the role of cellular glutathione peroxidase (Gpx1), a selenium-containing enzyme functioning in reduction of hydrogen peroxide and alkyl hyperoxides, in protecting animals against TBI, a line of Gpx1 transgenic mice was generated. Overexpression of Gpx1 was found in many organs including the brain of the transgenic mice. This line of transgenic mice and knockout mice deficient in Gpx1 were used in a model of controlled cortical impact injury and the efficiency of oxidative phosphorylation in brain mitochondria was determined. Although a 2-mm depth of mechanical impact caused a drastic decrease in NAD-linked electron transfer activities and energy-coupling capacities in brain mitochondria of nontransgenic mice, the decrease in mitochondrial function was completely prevented by overexpression of Gpx1 in Gpx1 transgenic mice. In addition, a 1-mm deformation depth hardly affected brain mitochondrial function in wild-type (Gpx1+/+) mice, yet resulted in a significant decrease in mitochondrial bioenergetic capacity in brains of homozygous Gpx1 knockout (Gpx1-/-) mice. Further experiments showed that inclusion of calcium chelator egtazic acid in measurement of mitochondrial respiration could completely restore the efficiency of mitochondrial respiration in injured brains of nontransgenic mice and Gpx1-/- mice, suggesting that the observed mitochondrial dysfunction is a direct result of increase in mitochondrion-associated calcium, which is secondary to the increased oxidative stress. These studies not only establish the role of Gpx1 in preventing mitochondrial dysfunction in mouse brain after TBI, but also suggest the species of reactive oxygen responsible for this event.

Analysis of hemostasis alterations in sepsis

This laboratory study tested new methods to analyze hemostasis alterations in septic patients. Samples of ethylenediamine tetraacetic acid (EDTA) plasma and citrated plasma were collected from 62 patients with clinical diagnosis of sepsis. Additionally, a subset of EDTA-plasma samples from each patient was stabilized 1 + 1 with 2.5 mol/l arginine, pH 8.6, to conserve the real hemostasis activation state. EDTA-arginine plasma, EDTA plasma and citrated plasma samples were tested in duplicate. The patients at admission to the intensive care unit had 36 +/- 26 (normal, 0.8 +/- 0.2) ng/ml global endotoxin reactivity, 188 +/- 66% (normal, 100 +/- 20%) fibrinogen function, 179 +/- 66% (normal, 100 +/- 20%) fibrinogen antigen, 4.0 +/- 3.6 (normal, 0.049 +/- 0.025) microg/ml D-dimer, 313 +/- 307% (normal, 100 +/- 30%) plasmin-antiplasmin complex, 8.7 +/- 11.4 (normal, 1.1 +/- 0.7) U/ml plasminogen activator inhibitor-1, 12.1 +/- 10.5 (normal, 1.3 +/- 0.4) ng/ml thrombin-antithrombin III complex, 173 +/- 62% (normal, 100 +/- 20%) thrombin, 568 +/- 225 (normal, 140 +/- 42) pg/ml tissue factor, and 2.56 +/- 2.48 (normal, 0.19 +/- 0.04) microg/ml soluble intercellular adhesion molecule-1. Endotoxin (lipopolysaccharide and/or beta-glucan) reactivity (EDTA plasma), fibrinogen function + antigen + ratio and plasminogen activator inhibitor-1 (citrated plasma), and D-dimer, soluble intercellular adhesion molecule-1, thrombin activity (EDTA-arginine-stabilized plasma) presented large aberrations in septic patients when compared with normal values and may therefore be particularly interesting as markers of hemostasis alteration. Whether the observed alterations are of clinical significance has to be determined in well defined patient groups.

Reactive oxygen species: toxic molecules or spark of life?

Increases in reactive oxygen species (ROS) and tissue evidence of oxidative injury are common in patients with inflammatory processes or tissue injury. This has led to many clinical attempts to scavenge ROS and reduce oxidative injury. However, we live in an oxygen rich environment and ROS and their chemical reactions are part of the basic chemical processes of normal metabolism. Accordingly, organisms have evolved sophisticated mechanisms to control these reactive molecules. Recently, it has become increasingly evident that ROS also play a role in the regulation of many intracellular signaling pathways that are important for normal cell growth and inflammatory responses that are essential for host defense. Thus, simply trying to scavenge ROS is likely not possible and potentially harmful. The 'normal' level of ROS will also likely vary in different tissues and even in different parts of cells. In this paper, the terminology and basic chemistry of reactive species are reviewed. Examples and mechanisms of tissue injury by ROS as well as their positive role as signaling molecules are discussed. Hopefully, a better understanding of the nature of ROS will lead to better planned therapeutic attempts to manipulate the concentrations of these important molecules. We need to regulate ROS, not eradicate them.

Anti-inflammatory effect of germanium-concentrated yeast against paw oedema is related to the inhibition of arachidonic acid release and prostaglandin E production in RBL 2H3 cells

1 To investigate anti-inflammatory activity of organic germanium, we measured the effect of germanium-concentrated yeast on arachidonic acid release, prostaglandin E(2) (PGE(2)) production, histamine release, and intracellular H(2)O(2) or hydroperoxide generation in RBL 2H3 cells, and carrageenan-induced paw oedema in rats. 2 Germanium-concentrated yeast dose-dependently inhibited carrageenan-induced paw oedema, suggesting that germanium-concentrated yeast has anti-inflammatory activity in acute inflammation. 3 Germanium-concentrated yeast significantly inhibited melittin-induced arachidonic acid release and PGE(2) production in RBL 2H3 cells. 4 Germanium-concentrated yeast did not affect melittin-induced histamine release and silica-induced intracellular H(2)O(2) or hydroperoxide generation in RBL 2H3 cells. 5 These results suggest that anti-inflammatory activity of germanium-concentrated yeast appears partly to be related to the inhibition of arachidonic acid release and PGE(2) production in RBL 2H3 cells.

The effect of acteoside on histamine release and arachidonic acid release in RBL-2H3 mast cells

The effect of acteoside, a phenylpropanoid glycoside isolated from Clerodendron trichotomum Thunberg, on histamine and arachidonic acid release was investigated in RBL 2H3 cells. Histamine was dose-dependently released from RBL 2H3 cells by melittin, arachidonic acid and thapsigargin. In extracellular Ca2+-free solution, basal secretion of histamine increased by two fold. The response of histamine release to melittin and thapsigargin in Ca2+-free solution was significantly decreased, whereas the response to arachidonic acid was significantly increased as compared with those in normal solution. Acteoside inhibited histamine release induced by melittin, arachidonic acid and thapsigargin in a dose-dependent manner in the presence or absence of extracellular Ca2+. However, the inhibitory activity of acteoside was more potent in normal solution than that in Ca2+-free solution. These data suggest that inhibitory mechanism of acteoside on histamine release may be related to extracellular Ca2+. On the other hand, acteoside significantly inhibited arachidonic acid release and prostaglandin E2 production induced by 0.5 microM melittin. It is possible that acteoside may be developed as an anti-inflammatory agent.

Quantification of uric acid, xanthine and hypoxanthine in human serum by HPLC for pharmacodynamic studies

A simple HPLC method was developed and validated for the determination of uric acid (UA), xanthine (X) and hypoxanthine (HX) concentrations in human serum to support pharmacodynamic (PD) studies of a novel xanthine oxidase inhibitor during its clinical development. Serum proteins were removed by ultrafiltration. The hydrophilic analytes and the I.S. were eluted by 100% aqueous phosphate buffer mobile phase. The hydrophobic matrix components (late peaks) were eluted with a step gradient of a higher organic mobile phase. Validation on linearity, sensitivity, precision, accuracy, stability, and robustness of the method for PD biomarkers (UA, X, and HX) was carried out in a similar manner to that for pharmacokinetic (PK) data where applicable. Issues of selectivity for endogenous biomarker analytes and individual concentration variations were addressed during method validation. Standards were prepared in analyte-free phosphate buffer. Quality control samples were prepared in control serum from individuals not dosed with the xanthine oxidase inhibitor. The method was simple and robust with good accuracy and precision for the measurement of serum UA, X, and HX concentrations.

Increased oxidative stress and altered levels of antioxidants in chronic obstructive pulmonary disease

An imbalance between oxidative stress and antioxidative capacity has been proposed to play an important role in the development and progression of chronic obstructive pulmonary disease. We carried out a study to assess the systemic oxidant-antioxidant status in patients with chronic obstructive pulmonary disease (COPD) and relate it to the severity of disease. We measured a wide range of parameters of oxidant-antioxidant balance in leukocytes, plasma and red cells of 82 patients with COPD and 22 healthy non-smoking controls (HNC). Lung function was measured by spirometry. Staging of COPD was done as per the recommended guidelines. Red cell antioxidative enzyme activities were altered, with glutathione peroxidase (GSH-Px) having lower, superoxide dismutase (SOD) having greater and catalase having similar activity in patients as compared to HNC. In plasma, ferric reducing antioxidant power (FRAP) and total protein sulfhydryls were lower and GSH-Px, lipid peroxides measured as MDA-TBA products, and protein carbonyls were higher in the patients as compared to HNC. Plasma total nitrates and nitrites (NO(x)) were similar in the two groups. Superoxide anion (O(2) (*-)) release from leukocytes upon stimulation with N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) and total blood glutathione were also higher in patients as compared to HNC. Plasma FRAP had a positive whereas total blood glutathione had a significant negative correlation with the severity of airways obstruction (FEV(1)% predicted). Further, comparisons between clinical stages of severity of COPD revealed significant differences in plasma FRAP and total blood glutathione. Our observations suggest there is a systemic oxidant-antioxidant imbalance in the patients with COPD.

Inhibition of atherogenesis in LDLR knockout mice by systemic delivery of adeno-associated virus type 2-hIL-10

Atherosclerosis is an inflammatory disease of the arteries. Interleukin-10 (IL-10) is known to be an anti-inflammatory cytokine which might be useful for counteracting the development of atherosclerosis. As long-term systemic cytokine delivery is prohibitively expensive, gene therapy might be a suitable approach. To test this idea, low-density lipoprotein receptor (LDLR) knockout mice were injected with recombinant adeno-associated virus type 2 (AAV)/interleukin-10 virus or AAV/granulocyte macrophage-colony stimulating factor (GM-CSF) virus and then put on a high-cholesterol diet. Upon harvesting the animals at 18 weeks, elevated blood lipids could be documented and AAV/IL-10 and AAV/GM-CSF DNA and mRNA could be found in various mouse organs. The mice receiving the AAV/IL-10 virus had significantly lower levels of atherogenesis (Sudan IV-staining and histology) than the untreated or the AAV/GM-CSF-treated animals, dropping from 53% to 17% (p < 0.05). The aortas of the AAV/IL-10-treated animals displayed higher IL-10 expression and lower CD68 and nitrotyrosine expression. These data are similar to those of Yoshioka et al. [Yoshioka, T, Okada, T, Maeda, Y, et al. Adeno-associatedvirus vector-mediated interleukin-10 gene transfer inhibits atherosclerosis in apolipoprotein E-deficient mice. Gene Ther 2004;11:1772-9] in which AAV/IL-10 was delivered into the tibial muscle of ApoE-deficient mice, instead of tail vein injection used here. These data indicate that systemic AAV/IL-10 gene delivery, with resulting inhibition of inflammation and oxidative stress, was able to limit atherogenesis, and suggest that this approach is worthy of further study.

NADPH oxidase mediates interleukin-6 expression in cerulein-stimulated pancreatic acinar cells

NADPH oxidase produces a large amount of reactive oxygen species (ROS) mainly in phagocytic cells. ROS are involved in NF-kappaB activation, cytokine expression and thus, pathogenesis of pancreatitis. However, the source of ROS in pancreatic acinar cells has not been clarified. Cerulein rapidly induces acute and edematous form of pancreatitis. We investigated whether pancreatic acinar cells contain NADPH oxidase, and whether NADPH oxidase mediates interleukin-6 (IL-6) in pancreatic acinar AR42J cells stimulated with cerulein. Expression of NADPH oxidase subunits and NADPH oxidase activity were determined in the cells by immunofluorescence staining and lucigenin luminescence, respectively. Oxidant-sensitive nuclear transcription factor NF-kappaB activation was monitored by electrophoretic mobility shift assay. IL-6 expression was determined by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbant assay. NADPH oxidase inhibitor diphenylene iodonium (DPI), antioxidant rebamipide, and antisense oligonucleotides (AS ODNs) for NADPH oxidase subunits p22phox and p47phox were used to determine the involvement of NADPH oxidase in NF-kappaB activation and IL-6 expression in AR42J cells. As a result, pancreatic acinar AR42J cells constitutively express NADPH oxidase subunits p67phox and p47phox in the cytosol and Nox1 and p22phox in the membrane. Cerulein-stimulated NADPH oxidase activity and induced NF-kappaB activation and IL-6 expression in AR42J cells. Treatment of DPI or rebamipide and transfection of AS ODNs for NADPH oxidase subunits suppressed cerulein-induced NF-kappaB activation and IL-6 expression compared to S ODNs. In conclusion, NADPH oxidase may mediate the expression of inflammatory cytokines by stimulating NF-kappaB activation in pancreatic acinar cells during the course of pancreatitis.

Isolation and analysis of partial cDNA sequence coding for superoxide dismutase in Wuchereria bancrofti

Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response.

NADPH oxidase and apoptosis in cerulein-stimulated pancreatic acinar AR42J cells

Apoptosis linked to oxidative stress has been implicated in pancreatitis. We investigated whether NADPH oxidase mediates apoptosis in cerulein-stimulated pancreatic acinar AR42J cells. We report here that cerulein treatment resulted in the activation of NADPH oxidase, as determined by ROS production, translocation of cytosolic subunits p 47(phox) and p 67(phox) to the membrane, and interaction between NADPH oxidase subunits. Cerulein induced Ca(2+) oscillation, the expression of apoptotic genes p53 and bax, and apoptotic indices (DNA fragmentation, TUNEL staining, caspase 3 activity, decrease in cell viability) in AR42J cells. Treatment with a Ca(2+) chelator, BAPTA-AM, or transfection with antisense oligonucleotides for NADPH oxidase subunits p22(phox) and p 47(phox) inhibited cerulein-induced ROS production, translocation of NADPH oxidase cytosolic subunits p 47(phox) and p 67(phox) to the membrane, and the expression of apoptotic genes and apoptotic indices, as compared to the cells without treatment and those transfected with the corresponding sense oligonucleotides. These results indicate that NADPH oxidase may mediate ROS-induced apoptosis in pancreatic acinar cells in a Ca(2+)-dependent manner.

Oxidative stress contributes to methotrexate-induced small intestinal toxicity in rats

BACKGROUND

Gastrointestinal toxicity is one of the most serious side effects in the methotrexate (MTX) treatment. However, the mechanism of the toxicity has not been completely clarified, which may be the reason why symptomatic therapy is carried out. On the other hand, the oxidative stress is known to play an important role in various diseases and drug-induced side effects. In this study the focus was on the oxidative stress in order to clarify the mechanism of MTX-induced small intestinal damage, especially neutrophil infiltration.

METHODS

MTX (20 mg/kg body wt) was administered to rats intravenously. Mucosal homogenates were prepared from the small intestine and used for assay of biochemical parameters, by which induction of oxidative stress and neutrophil infiltration were evaluated. N-acetylcysteine (NAC; 80 mg/kg body wt), an antioxidant or sodium tungstate (tungsten; 0.7 g/kg body wt), an inhibitor of xanthine dehydrogenase (XD)/xanthine oxidase (XO) known as an important source of reactive oxygen species (ROS) was given to rats with MTX to investigate the contribution of ROS to neutrophil infiltration.

RESULTS

The MTX treatment of rats induced the oxidative stress in the small intestine. The ROS production was seen preceding an increase of myeloperoxidase activity, which suggested neutrophil infiltration. Both treatments of NAC and tungsten prevented the MTX-induced ROS production and neutrophil infiltration.

CONCLUSIONS

These results suggest that oxidative stress plays an important role in the MTX-induced small intestinal damage, especially neutrophil infiltration. Thus, the modulation of oxidative stress would be useful in reducing intestinal damage in MTX treatment.

Virulence factors of Enterococcus faecalis: relationship to endodontic disease

Enterococcus faecalis is a micro-organism that can survive extreme challenges. Its pathogenicity ranges from life-threatening diseases in compromised individuals to less severe conditions, such as infection of obturated root canals with chronic apical periodontitis. In the latter situation, the infecting organisms are partly shielded from the defense mechanisms of the body. In this article, we review the virulence factors of E. faecalis that may be related to endodontic infection and the periradicular inflammatory response. The most-cited virulence factors are aggregation substance, surface adhesins, sex pheromones, lipoteichoic acid, extracellular superoxide production, the lytic enzymes gelatinase and hyaluronidase, and the toxin cytolysin. Each of them may be associated with various stages of an endodontic infection as well as with periapical inflammation. While some products of the bacterium may be directly linked to damage of the periradicular tissues, a large part of the tissue damage is probably mediated by the host response to the bacterium and its products.

Natural beta-carotene for the prevention of post-ERCP pancreatitis

OBJECTIVE

Endoscopic retrograde cholangiopancreatography (ERCP) is a commonly used procedure. Pancreatitis is its most common complication. As the injury may be mediated by oxidative stress, it could be ameliorated by antioxidants.

METHODS

We conducted a double-blind trial, giving the patients a single dose of natural beta-carotene or placebo, 12 hours prior to procedure, and monitoring them for 24 hours post-procedure for procedure complications, antioxidant levels, and plasma oxidation.

RESULTS

The overall incidence of acute pancreatitis according to our definition was 9.6%. The incidence of pancreatitis was not significantly different between the beta-carotene group (10%) and the placebo group (9.4%). Four patients in the placebo group had severe pancreatitis (2.22%), but none in the beta-carotene group. This difference is statistically significant.

CONCLUSION

We did not see a reduction in the incidence of post-ERCP pancreatitis, but there may be some protective effect of treatment with beta-carotene regarding the severity of disease.

Alleviating ischemia-reperfusion injury in small bowel

An amino acid-based solution has been recently developed and has demonstrated significant protective effects during cold storage of small bowel (SB). This study was designed to examine the role of this novel solution in ameliorating intestinal injury in an in vivo model of ischemia-reperfusion (IR). The impact of luminal treatment with an amino acid-based (AA) solution was assessed throughout reperfusion after 60-min warm ischemia (WI) in rodent SB. Energetics (ATP and total adenylates) remained significantly elevated throughout 60-min reperfusion in AA-treated tissue compared with untreated controls. Increases in end-products (ammonia and alanine) and increases in alanine aminotransferase and glutaminase activity implicated greater amino acid metabolism in AA-treated tissues. After reperfusion, malondialdehyde levels were similar between all groups. Glutathione levels were consistently elevated in AA-treated tissues and by 60 min reperfusion values were sixfold greater than control. AA-mediated protection during IR resulted in reduced neutrophil infiltration suggesting a weaker inflammatory response. Barrier function and electrophysiology parameters exhibited a clear pattern of mucosal preservation in AA-treated tissues; histology supported these findings. This study raises the possibility of a role for a luminal nutrient-rich solution during ischemic storage of small bowel in the clinic.

Oxidative stress induces nuclear loss of DNA repair proteins Ku70 and Ku80 and apoptosis in pancreatic acinar AR42J cells

Cell death linked to oxidative DNA damage has been implicated in acute pancreatitis. The severe DNA damage, which is beyond the capacity of the DNA repair proteins, triggers apoptosis. It has been hypothesized that oxidative stress may induce a decrease in the Ku70 and Ku80 levels and apoptosis in pancreatic acinar cells. In this study, it was found that oxidative stress caused by glucose oxidase (GO) acting on beta-d-glucose, glucose/glucose oxidase (G/GO), induced slight changes in cytoplasmic Ku70 and Ku80 but drastically induced a decrease in nuclear Ku70 and Ku80 both time- and concentration-dependently in AR42J cells. G/GO induced apoptosis determined by poly(ADP-ribose) polymerase cleavage, an increase in expression of p53 and Bax, and a decrease in Bcl-2 expression. G/GO-induced apoptosis was in parallel with the loss of nuclear Ku proteins in AR42J cells. Caspase-3 inhibitor prevented G/GO-induced nuclear Ku loss and cell death. G/GO did not induce apoptosis in the cells transfected with either the Ku70 or Ku80 expression gene but increased apoptosis in those transfected with the Ku dominant negative mutant. Pulse and pulse-chase results show that G/GO induced Ku70 and Ku80 syntheses, even though Ku70 and Ku80 were degraded both in cytoplasm and nucleus. G/GO-induced decrease in Ku binding to importin alpha and importin beta reflects possible modification of nuclear import of Ku proteins. The importin beta level was not changed by G/GO. These results demonstrate that nuclear decrease in Ku70 and Ku80 may result from the decrease in Ku binding to nuclear transporter importins and the degradation of Ku proteins. The nuclear loss of Ku proteins may underlie the mechanism of apoptosis in pancreatic acinar cells after oxidative stress.

Minalrestat and leukocyte migration in diabetes mellitus

BACKGROUND

We recently demonstrated that aldose reductase inhibition was effective in restoring the reduced migratory capacity of leukocytes in diabetic rats. To investigate the mechanism(s) involved in the restoring effect, we used minalrestat, an aldose reductase inhibitor.

METHODS

In sodium pentobarbital-anesthetized (40 mg/kg, intraperitoneally) alloxan-diabetic or galactosemic male Wistar rats, the internal spermatic fascia was exteriorized, and the number of leukocytes rolling along the venular endothelium and the number of leukocytes sticking to the vascular wall after topical application of zymosan-activated plasma or leukotriene B(4) (1 ng/ml), as well as after the application of a local irritant stimulus (carrageenan, 100 microg), were determined using intravital microscopy. Data from animals that were treated with and those that were not treated with minalrestat (10 mg/kg/d by gavage) were compared.

RESULTS

The reduced number of leukocytes rolling along the venular endothelium (by about 70%) and the number of adhered and migrated leukocytes in postcapillary venules (by 60%) were significantly restored to control values after minalrestat treatment. Total or differential leukocyte counts, venular blood flow velocity or wall shear rate were not altered by minalrestat treatment. The expression of ICAM-1 and P-selectin, cell adhesion molecules involved in the interaction of leukocyte-endothelium, reduced in diabetic rats was restored by minalrestat treatment.

CONCLUSION

We conclude that an enhanced flux through the polyol pathway might be involved in the reduced expression of ICAM-1 and P-selectin contributing to the impaired leukocyte-endothelial interactions in diabetes mellitus and that aldose reductase inhibition restores the defect, restoring the reduced expression.

Inflammatory cells in rat skeletal muscle are elevated after electrically stimulated contractions

We determined the effect of muscle contractions resulting from high-frequency electrical stimulation (HFES) on inflammatory cells in rat tibialis anterior (TA), plantaris (Pln), and soleus (Sol) muscles at 6, 24, and 72 h post-HFES. A minimum of four and a maximum of seven rats were analyzed at each time point. HFES, applied to the sciatic nerve, caused the Sol and Pln to contract concentrically and the TA to contract eccentrically. Neutrophils were higher (P < 0.05) at 6 and 24 h after HFES in the Sol, Pln, and TA muscles relative to control muscles. ED1(+) macrophages in the Pln were elevated at 6 and 24 h after HFES and were also elevated in the Sol and TA after HFES relative to controls. ED2(+) macrophages in the Sol and TA were elevated at 24 and 72 h after HFES, respectively, and were also elevated in the Pln after HFES relative to controls. In contrast to the TA muscles, the Pln and Sol muscles showed no gross histological abnormalities. Collectively, these data indicate that both eccentric and concentric contractions can increase inflammatory cells in muscle, regardless of whether overt histological signs of injury are apparent.

Suppression of cerulein-induced cytokine expression by antioxidants in pancreatic acinar cells

Reactive oxygen species (ROS) has been considered to be an important regulator in the development and pathogenesis of pancreatitis and an activator of the transcription factor, nuclear factor-kappaB (NF-kappaB), regulating inflammatory cytokine gene expression. NF-kappaB activation was demonstrated in cerulein pancreatitis, which rapidly induces an acute, edematous form of pancreatitis. This study aimed to investigate whether cerulein induced ROS generation, lipid peroxide and hydrogen peroxide production, NF-kappaB activation, and expression of cytokines (IL-1beta, IL-6) in pancreatic acinar cells. An additional aim was to establish whether these alterations were inhibited by antioxidants such as glutathione, superoxide dismutase, and catalase and an inhibitor of NF-kappaB activation, pyrrolidine dithiocarbamate (PDTC). To determine the possible interactions of the antioxidants and PDTC with cerulein-induced signaling, Ca2+ signal and amylase release were monitored in the pancreatic acinar cells treated with cerulein in the presence or absence of either the antioxidants or PDTC. The results showed that cerulein generated ROS and increased lipid peroxide and hydrogen peroxide production in the acinar cells, as determined by dichlorofluorescein diacetate dye. This resulted in NF-kappaB activation and the induction of cytokine gene expression in the cells. The cerulein-induced NF-kappaB activation was in parallel to IkappaBalpha degradation. Cerulein also induced Ca2+ signals and amylase release in acinar cells. Both antioxidants (glutathione, superoxide dismutase, catalase) and PDTC inhibited the cerulein-induced, oxidant-mediated alterations but did not affect the cerulein-evoked Ca2+ signals and amylase release in acinar cells. In conclusion, ROS, generated by cerulein, activates NF-kappaB, resulting in the up-regulation of inflammatory cytokine gene expression in acinar cells. NF-kappaB inhibition by scavenging ROS might alleviate the inflammatory response in pancreatic acinar cells by suppressing cytokine gene expression.

Histamine release by hydrochloric acid is mediated via reactive oxygen species generation and phospholipase D in RBL-2H3 mast cells

In order to investigate the underlying mechanism of HCl in oesophagitis, the inflammatory response to HCl was observed in RBL-2H3 mast cells. Rat basophilic leukemia (RBL-2H3) cells were used to measure histamine release, arachidonic acid (AA) release, reactive oxygen species (ROS) and peroxynitrite generation induced by HCl. Exogenous HCl increased the level of histamine release and ROS generation in a dose dependent manner, whereas it decreased the spontaneous release of [3H] AA and the spontaneous production of peroxynitrite. Mepacrine (10 microM), oleyloxyethyl phosphorylcholine (10 microM) and bromoenol lactone (10 microM) did not affect both the level of histamine release and ROS generation induced by HCl. U73122 (1 microM), a specific phospholipase C (PLC) inhibitor did not have any influence on level of histamine release and ROS generation. Propranolol (200 microM), a phospholipase D (PLD) inhibitor, and neomycin (1 mM), a nonspecific PLC and PLD inhibitor, significantly inhibited both histamine release and ROS generation. Diphenyleneiodonium (10 microM), a NADPH oxidase inhibitor, and tiron (5 mM), an intracellular ROS scavenger significantly inhibited the HCl-induced histamine release and ROS generation. These findings suggest that the inflammatory responses to HCl is related to histamine release and ROS generation, and that the ROS generation by HCl may be involved in histamine release via the PLD pathway in RBL-2H3 cells.

Xanthine oxidoreductase activity in human liver disease

OBJECTIVES

The aim of this study was to investigate the level and the form of xanthine oxidoreductase (XOR) in severely diseased human livers, to ascertain whether the modifications of the enzyme activity reported in experimental pathology also occur in human liver disease.

METHODS

Total, dehydrogenase, and oxidase activities of XOR were measured in samples of human liver removed for transplantation or partial hepatectomy. Samples included four groups: 1) histologically normal liver tissue, adjacent to metastases from extrahepatic tumors (controls), 2) liver with virus-related cirrhosis; 3) liver with virus-negative cirrhosis, and 4) hepatocellular carcinoma tissue (HCC).

RESULTS

The level of total XOR was significantly higher in liver with virus-related cirrhosis, but not in virus-negative cirrhosis, than in controls. In virus-positive cirrhosis, the total XOR activity correlated positively with the level of ALT. The percentage of XOR oxidase activity in cirrhotic liver, regardless of virus infection, correlated positively with aspartate amino-transferase, bilirubin concentration, and partial thromboplastin time, and negatively with prothrombin time. The activity of XOR was significantly lower in HCC than in control tissue or in a nonneoplastic area of the same liver.

CONCLUSIONS

Consistent with previous reports in experimental pathology, the level of XOR was increased in cirrhotic liver, in association with viral infection. This increment correlated with ALT, suggesting a relationship between XOR activity and the extent of liver injury caused by viral replication. The percentage of oxidase activity seems to be correlated with tissue damage and consequent liver impairment. The low XOR activity observed in HCC is consistent with reported experimental pathology.

Muscle inflammatory cells after passive stretches, isometric contractions, and lengthening contractions

We tested the hypotheses that lengthening contractions, isometric contractions, and passive stretches increase muscle inflammatory cells (neutrophils and macrophages) and that prior conditioning with lengthening contractions, isometric contractions, or passive stretches reduces neutrophils and macrophages after subsequent lengthening contractions. Extensor digitorum longus muscles in anesthetized mice were subjected in situ to lengthening contractions, isometric contractions, or passive stretches. Six hours or 3 days after a protocol of contractions or passive stretches, neutrophils and macrophages were quantified in muscle cross sections. Three days after isometric contractions or passive stretches, neutrophils were elevated (P < 0.05) 3.7- and 5.5-fold, respectively, relative to controls. Both macrophages and neutrophils were increased 51.2- and 7.9-fold, respectively, after lengthening contractions. Prior lengthening contractions, isometric contractions, or passive stretches reduced inflammatory cells after lengthening contractions performed 2 wk later. The major finding of this study was that passive stretches and isometric contractions elevated neutrophils without causing overt signs of injury. Because both passive stretches and isometric contractions elevated neutrophils and afforded some protection from contraction-induced muscle injury, neutrophils and/or the related inflammatory events may contribute to the induction of a protective mechanism.

Antioxidant superoxide dismutase - a review: its function, regulation in the testis, and role in male fertility

Extracellular superoxide dismutase (SOD(EX)), an antioxidant enzyme, was found to be present in the testis at a relatively high concentration versus other organs. In a more detailed survey of several rat tissues and cells by reverse transcriptase-polymerase chain reaction, it was shown that germ cells expressed approximately one-third that of Sertoli cells, suggesting both cell types are equipped with the machinery needed to defend themselves from radical-induced damage. When we used an in vitro model in which germ cells were co-cultured with Sertoli cells at a Sertoli:germ cell ratio of 1:1, we failed to detect any changes in the mRNA level of SOD(EX). However, the addition of increasing concentrations of germ cell secretory proteins into Sertoli cell cultures resulted in a decrease in Sertoli cell SOD(EX) expression, illustrating that germ cells can indeed regulate Sertoli cell SOD(EX). On the other hand, Sertoli cell SOD(EX) expression was stimulated when human recombinant interleukin-1alpha (IL-1alpha), a germ cell product, was included into Sertoli cells in vitro. These results, taken collectively, suggest SOD(EX) is an important antioxidant molecule in the testis that is under germ cell regulation.

Oxidative stress to human lymphocytes by xanthine oxidoreductase activity

The in vitro toxicity of the reactive oxygen species generating enzyme xanthine oxidoreductase (XOR) to human peripheral blood lymphocytes was studied after stimulation with phytohaemoagglutinin or anti-CD3/CD28 antibodies. Apoptosis and necrosis were induced by the XOR/hypoxanthine system in a time- and concentration-dependent manner. CD8+ lymphocytes showed a higher sensitivity than CD4+ cells to the XOR/hypoxanthine system. The occurrence of apoptosis was demonstrated by annexin-V binding to injured cell membrane, which was the most precocious alteration observed, followed by the increment of transglutaminase activity, which was significant at the lowest XOR concentration used. Nuclear damage was assessed by the increased hypodiploid nuclei and by DNA migration on gel electrophoresis, which turned to an apoptotic pattern before the occurrence of cell membrane necrotic lesions. Apoptosis was induced by XOR activity proportionally to substrate concentration and was prevented by the competitive enzyme inhibitor, allopurinol. The hydrogen peroxide scavenging enzyme, catalase, gave a higher protection than superoxide dismutase from the toxicity caused by the XOR/hypoxanthine system. Necrosis occurs in a variable percentage indicating that reactive oxygen species may trigger both apoptosis and necrosis in proliferating human lymphocytes, mostly depending on XOR concentration.

Ferroxidases and xanthine oxidase in plasma of healthy newborn infants

In the neonatal period, there is a high iron load, while both the level and molar oxidase activity of ceruloplasmin are low. On the other hand, the neonatal xanthine oxidase (XO) activity is higher than later in life and XO has a significant iron-oxidizing capacity. We therefore studied the physiological contribution of XO to the ferroxidase activity of the plasma in 20 full-term newborn infants. Ferroxidase activity was measured spectrophotometrically, with Fe++ as substrate. The uric acid formed by XO was assayed by means of HPLC, with electrochemical detection. The total ferroxidase activity in the plasma was about one-fourth of the adult level and rapidly increased doubling within 3 days after birth. About 90% of the plasma ferroxidase activity was due to ceruloplasmin, the remainder being accounted for by ferroxidase II. The XO activity underwent a 30% (statistically non-significant) elevation at 24 h, though ferroxidase activity attributable to XO was not detected at any time. Accordingly, XO does not seem to add substantially to the total iron-oxidizing capacity of the plasma in the neonatal period. The high molar ferroxidase activity is probably of importance at the endothelial cell surface.

Free radical scavenging active components from Cedrus deodara

An activity-directed fractionation and purification process was used to identify the antioxidant components of Cedrus deodara. Dried heartwood powder of C. deodara was first defatted with petroleum ether and then extracted with chloroform. The chloroform extract showed strong antioxidant activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. This fraction was then subjected to separation and purification using silica gel column chromatography. Three compounds with potent antioxidant activity were isolated in significant yields and identified by spectroscopic methods ((1)H NMR, (13)C NMR, IR, and MS). They were identified as (-)-matairesinol, (-)-nortrachelogenin, and a dibenzylbutyrolactollignan (4,4',9-trihydroxy-3,3'-dimethoxy-9,9'-epoxylignan). This is the first report of the occurrence of these compounds in C. deodara.

The vaccinia virus superoxide dismutase-like protein (A45R) is a virion component that is nonessential for virus replication

A characterization of the A45R gene from vaccinia virus (VV) strain Western Reserve is presented. The open reading frame is predicted to encode a 125-amino-acid protein (M(r), of 13,600) with 39% amino acid identity to copper-zinc superoxide dismutase (Cu-Zn SOD). Sequencing of the A45R gene from other orthopoxviruses, here and by others, showed that the protein is highly conserved in all viruses sequenced, including 16 strains of VV, 2 strains of cowpox virus, camelpox virus, and 4 strains of variola virus. In all cases the protein lacks key residues involved in metal ion binding that are important for the catalytic activity. The A45R protein was expressed in Escherichia coli, purified, and tested for SOD activity, but neither enzymatic nor inhibitory SOD activity was detected. Additionally, no virus-encoded SOD activity was detected in infected cells or purified virions. A monoclonal antibody raised against the A45R protein expressed in E. coli identified the A45R gene product as a 13.5-kDa protein that is expressed late during VV infection. Confocal microscopy of VV-infected cells indicated that the A45R protein accumulated predominantly in cytoplasmic viral factories. Electron microscopy and biochemical analyses showed that the A45R protein is incorporated into the virion core. A deletion mutant lacking the majority of the A45R gene and a revertant virus in which the deleted gene was restored were constructed and characterized. The growth properties of the deletion mutant virus were indistinguishable from those of wild-type and revertant viruses in all cell lines tested, including macrophages. Additionally, the virulence and pathogenicity of the three viruses were also comparable in murine and rabbit models of infection. A45R is unusual in being the first VV core protein described that affects neither virus replication nor virulence.

Exercise at old age: does it increase or alleviate oxidative stress?

Aging is associated with increased free radical generation in the skeletal muscle that can cause oxidative modification of protein, lipid, and DNA. Physical activity has many well-established health benefits, but strenuous exercise increases muscle oxygen flux and elicits intracellular events that can lead to increased oxidative injury. The paradox arises as to whether exercise would be advisable to aged population. Research evidence indicates that senescent organisms are more susceptible to oxidative stress during exercise because of the age-related ultrastructural and biochemical changes that facilitate formation of reactive oxygen species (ROS). Aging also increases the incidence of muscle injury, and the inflammatory response can subject senescent muscle to further oxidative stress. Furthermore, muscle repair and regeneration capacity is reduced at old age that could potentially enhance the accrual of cellular oxidative damage. Predeposition of certain age-related pathologic conditions may exacerbate the risks. In spite of these risks, the elderly who are physically active benefit from exercise-induced adaptation in cellular antioxidant defense systems. Improved muscle mechanics, strength, and endurance make them less vulnerable to acute injury and chronic inflammation. Many critical questions remain regarding the relationship of aging and exercise as we enter a new millennium. For example, how does aging alter exercise-induced intracellular and intercellular mechanisms that generate ROS? Can acute and chronic exercise modulate the declined gene expression of metabolic and antioxidant enzymes seen at old age? Does exercise prevent age-dependent muscle loss (sarcopenia)? What kinds of antioxidant supplementation, if any, do aged people who are physically active need? Answers to these questions require highly specific research in both animals and humans.

Elevated secretion of myeloperoxidase by neutrophils from asthmatic patients: the effect of immunotherapy

BACKGROUND

There is increasing evidence of neutrophil participation in asthma and the allergic process. After activation, neutrophils release myeloperoxidase (MPO) together with other granule enzymes.

OBJECTIVES

In this study we attempted to evaluate the release of MPO in vitro by neutrophils from asthmatic patients and the relationship between neutrophil degranulation and lung function, measured as FEV(1), of the patients. We also investigated the possible role of immunotherapy in the release of MPO by neutrophils.

METHODS

Neutrophils were stimulated with formyl-methionyl-leucyl-phenylalanine for 45 minutes at 37 degrees C. MPO released from neutrophils was assayed by using an MPO enzyme immunoassay.

RESULTS

Neutrophils released statistically significantly higher MPO levels in the asthmatic patients not receiving immunotherapy than in the healthy group. A significant inverse correlation was observed in the asthmatic group not receiving immunotherapy between MPO secretion and lung function, measured as FEV(1), of the patients. Neutrophils of the asthmatic group receiving immunotherapy released significantly less MPO than did those of the asthmatic group not receiving immunotherapy, with MPO levels equal to those from nonallergic subjects.

CONCLUSIONS

We conclude that neutrophils obtained from allergic asthmatic patients have an increased propensity to release MPO. The experiments described here provide evidence that there is a significant inverse relationship between levels of MPO released by neutrophils from allergic patients and lung function, as assessed by FEV(1). Our study suggests that immunotherapy actively modifies the release of MPO in vitro by neutrophils from allergic asthmatic patients.

Serum xanthine oxidase in human liver disease

OBJECTIVES

High concentrations of serum xanthine oxidase (XO) have been reported during human liver disease and hepatocyte injury in experimental settings. However, it is unclear whether this elevation reflects hepatocyte necrosis or has a different meaning.

METHODS

The serum level of XO in 64 patients with chronic liver disease (17 patients with cirrhosis, 30 with chronic hepatitis, and 17 with cholestatic disorders) and in 12 control subjects was determined by a competitive ELISA. Conventional serum markers of liver damage were assessed in all patients, and grading and staging were scored in the chronic hepatitis group according to Knodell.

RESULTS

The XO serum levels were significantly higher in the patients than in the controls. The differences were also significant when controls were compared to patients with chronic hepatitis and cholestatic disorders separately, but not when compared to the cirrhosis group. Patients with cholestatic disorders had XO values higher than those of patients with cirrhosis or chronic hepatitis. XO levels did not correlate with stage and grade in chronic hepatitis group. We found a weak but significant positive correlation in patients between XO serum level and gamma-glutamyl transpeptidase (r = 0.37). This correlation was stronger when chronic hepatitis (r = 0.42) and, especially cholestatic disorders (r = 0.71), were separately tested, but was absent in the cirrhosis group. The XO values positively correlated with alkaline phosphatase in patients with cholestatic disorders. A level of serum XO >32 microg/ml specifically identified cholestatic disorders in our study population.

CONCLUSIONS

A marked elevation of serum XO in patients with chronic liver disease seems to reflect the presence of cholestasis. No correlation between XO levels and histological or serum evidence of hepatocyte necrosis was found in these patients.

Elevated superoxide production by active H-ras enhances human lung WI-38VA-13 cell proliferation, migration and resistance to TNF-alpha

Accumulating evidence has suggested that cellular production of superoxide acts as an intracellular messenger to regulate gene expression and modulate cellular activities. In this report, we set out to investigate the role of active H-ras-mediated superoxide production on tumor cell malignancy in a SV-40 transformed human lung WI-38 VA-13 cell line. Stable transfection and expression of constitutively active mutant V12-H-ras (V12-H-ras) dramatically increased intracellular production of superoxide. The expression of V12-H-ras significantly enhanced cell proliferation, migration and resistance to TNF-alpha treatment compared to that of parental and vector control cells, while expression of wild type H-ras (WT-H-ras) only had modest effects. Upon scavenging by superoxide dismutase and other molecules that decrease the intracellular level of active H-ras mediated superoxide production, cell proliferation, migration and resistance to TNF-alpha were significantly reduced. Furthermore, we demonstrated that the activation of membrane NADPH oxidase activity by expression of active H-ras contributed to the intracellular superoxide production. The causal relationship between membrane superoxide production and increased cell proliferation, migration, and resistance to TNF-alpha by the expression of active H-ras, has provided direct evidence to demonstrate that superoxide acts as an intracellular messenger to cascade ras oncogenic signal relay and to modulate tumor malignant activity.

The anti-inflammatory effects of human recombinant copper-zinc superoxide dismutase on pulp inflammation

Inflammation in the dental pulp is accompanied by release of a wide variety of highly oxidative molecules known as reactive oxygen species (ROS). ROS concentrations are controlled in vivo by an antioxidant enzyme scavenger system that may be overwhelmed by the increases in ROS production seen during inflammation. Supplementation of the antioxidant defense system, therefore, may limit the severity of the inflammatory response to injury due to this component. To test this hypothesis, this study examined the effects of superoxide radical scavenging on pulpal inflammation induced in rat molars by standardized cavity preparation. The extent of pulp inflammation was compared histomorphometrically between animals treated with exogenous administration of a human recombinant antioxidant enzyme, copper-zinc superoxide dismutase, conjugated to polyethylene glycol (hr-CuZn-SOD), versus saline-vehicle controls. There was a statistically significant reduction in area of inflammation involvement in those animals treated with hrCuZn-SOD, compared with controls. Although hrCuZn-SOD administration did not completely eliminate inflammation in all animals treated, there was a statistically significant lessening of the severity of the inflammatory response, as well as a greater degree of reparative dentin observed in the hrCuZn-SOD-treated animals.